The airplane may not know it's dark, but the pilot does, and the accident record shows it. AVweb's Thomas P. Turner helps reduce the risk of night flight.
Countering the argument that "The airplane doesn't know if it's light or dark," the record clearly shows a greater number of aircraft accidents at night. The AOPA Air Safety Foundation's Nall Report of general aviation accident statistics shows the increased hazard of flying at night. According to the 2007 edition of the report, "... only 19.2 percent of daytime accidents resulted in fatalities, but over one-third (34.6 percent) of all night accidents were fatal ... At night, nearly half of the accidents in VMC conditions were fatal ... compared to nearly three-fourths of night IMC accidents." There's a lot of added risk to flying in the dark. How can we minimize that risk?
At night, what might otherwise be inconveniences can become life-threatening emergencies. If confession is good for the soul, then my spirit will get a double-dose of medicine this month. Both experiences I am about to relate occurred at night, very early in my flying career, and in retrospect were incredibly stupid.
My mechanic had just signed off the annual on my 1946 Cessna 120. I had hoped to get the entire inspection on this simple airplane done in a day, but as a backup, I had arranged to stay at a friend's home if we didn't finish up. (I was a roughly two-hour flight from home.) I'd even given myself a deadline: If the airplane wasn't buttoned up and ready to go by 4 p.m., I'd call my friend and have him pick me up.
The inspector had found a little surface corrosion on an aileron fitting, and I had a little trouble reinstalling it (under the mechanic's supervision) after sandblasting and painting. That ate into my "launch" time, and it was about 4:45 p.m. before everything was closed up signed off. Thinking I could still beat the darkest night home (it was October), and with verified reports of very clear VMC for hundreds of miles around, I cast off my earlier plan, threw my overnight bag behind the antique Cessna's seat and turned on the master switch ... but didn't have the power to crank the engine.
I rationalized that I must've shorted the battery when I removed it to clean the battery box during annual, so I did what any good taildragger pilot would do: I got my mechanic to sit in the copilot's seat while I hand-propped the little Continental engine, then jumped in and bid him farewell. A few minutes after 5 p.m. (more than an hour after my "no-go" time), I took off and headed west. Already the first auto and house lights were glowing in the autumn dusk.
My battery seemed to charge all right, but an hour and a half later I was over very dark prairie east of Wichita when all my lights failed. I was alone, in the dark, with only a flashlight to show the way. I passed just south of a well-lighted runway, knowing my home 'drome sported 24-hour runway lighting. I already had the intense gas flame of a refinery near my destination in sight, so navigating in the clear, dark skies was easy. Only when I lined up with my home runway did I realize I didn't have a landing light, and in a three-point landing stance I would loose sight of anything straight ahead. Somehow my wheels kissed the pavement; I taxied clear and shut down. Only when I climbed out and stood on the tarmac did it occur to me how incredibly stupid most of my decisions had been that night, and how much my choices sounded like the write-up from a fatal NTSB report.
A year or so later I was tasked to fly a Beech Baron from its base in northern Kansas down to Wichita. I hitched a ride up with a coworker in a Piper Warrior and, after inspecting the Baron and its logbooks, waved him homeward. We'd had stronger-than-expected headwinds on the way up, delaying my departure just enough so it would get dark before I got back home. I fired up the piston twin and took off, VFR, southward -- the first time I'd every flown that particular Baron.
About half an hour out of Wichita, I noticed a ground fog developing. ATIS at Wichita Mid-Continent reported IFR conditions but well above minimums, so I called Center and picked up an IFR clearance in the air (ah, the Midwest). About the time I was on a vector to intercept the localizer for the ILS, as it was getting dark enough, I turned on the instrument panel lights. Nothing happened. It's hard to check panel lights for operation in daylight, but what I later learned was a faulty rheostat prevented them from coming on when I needed them. I'd not gone out of my way to shade the instruments and check that panel lights worked before I took off, knowing I'd be flying at night. What followed was the classic "flashlight in the mouth" approach set-up and landing, at least until I was low enough on the approach that the runway lights shone through the fog.
There are a lot of "I should've done this" or "I should not have done that" in both these stories, lessons I've absorbed and integrated since that time. I'm sure in reading my confessions you've thought of some of the same things. But re-living these two potential disasters, and reviewing dozens of nighttime NTSB reports, I've come up with some techniques for minimizing the risk for night flight.
There's an old saw about engine failures at night: If the engine quits, turn on the landing light. If you don't like what you see, turn off the landing light.
Many pilots feel night, single-engine flight is too risky. Others say the engine doesn't know it's dark outside, and it's not more likely to quit. That's true, but it's also true that most multiengine airplanes have better electrical and other system redundancy than most single-engine airplanes.
If engine reliability itself is what worries you, however, you can avoid the greatest likelihood of engine failure by practicing good fuel management. My research of NTSB reports shows that well over three-fourths of all nighttime engine failures result from either fuel starvation (running out of fuel in the tank feeding the engine and not switching to another tank with fuel in it before hitting the ground) or fuel exhaustion (truly "running out of gas").
Whether you're flying a single-engine airplane or a twin, to avoid the most likely engine failure:
Other than fuel mismanagement, engines rarely quit without at least some warning. Monitor engine indications (oil temperature and pressure, fuel-flow rates or pressure, cylinder-head and exhaust-gas temperatures, ammeter or voltage meter) in flight and record the indications over a series of daylight trips. You'll likely find that all indications are quite steady and predictable from flight to flight. Record "normal" indications and frequently compare those to what you actually observe on later flights. You might even use a grease pencil to mark the "normal" needle position for each instrument in your airplane. You'll not only be able to tell your oil pressure is "in the green," but, more accurately, it's precisely what is "normal" for that engine.
There's a lot more to know about night flight, including a good section in the Airplane Flying Handbook (FAA-H-8030-3A), Chapter 10. Using that knowledge safely hinges on your ability to manage the risks of night flying.
Fly safe, and have fun!